The correct answer is C.
OBJ-1.3: 10GBase-SR is a 10 Gigabit Ethernet LAN standard for use with multimode fiber optic cables using short-wavelength signaling. 100Base-TX and 10GBase-T are ethernet standards that use copper wiring. 10GBase-LR is a standard for 10 Gigabit Ethernet over single-mode fiber optic cabling. For the exam, remember the memory aid, “S is not single,” which means that if the naming convention contains Base-S as part of its name then it uses a multimode fiber cable.